Antimicrobial adhesive and coating substance and method for the production thereof

ABSTRACT

The invention relates to an antimicrobial adhesive and coating material which contains as the antimicrobial component metallic silver particles with a content of less than 5 ppm of silver, sodium and potassium ions.

The invention relates to an antimicrobial adhesive and coating material,a use of the adhesive and coating material and a method of manufacturingsame.

The invention relates to the area of adhesive and coating materials for,in the broadest sense, medical, technical-medical or technical-hygienicapplications. Antimicrobial adhesive and coating materials are used inparticular for manufacturing plaster bandages, wound coverings,catheters, hygienic packaging materials, for coating the aforementionedmaterials as well as for coating components of technical medical devicesand walls of rooms which must kept hygienic and similar. The use of suchadhesive and coating materials is intended to prevent the invasion ofmicro-organisms.

From DE 199 58 458 A1 an antimicrobial wound covering is known. Thewound covering is made of a synthetic polymer material containingzeolites containing metal-ions.

U.S. Pat. No. 6,124,374 describes an antimicrobial adhesive cream fordentures. The antimicrobial active substance used here are 2-valencecopper salts.

From U.S. Pat. No. 6,216,699 B1 a pressure-sensitive adhesive substanceis know to which diidomethyl-p-tolylsulfon is added as antimicrobialactive substance.

The known antimicrobial constituents are not particularly universal.They are specifically adjusted to the particular matrix. Theantimicrobial effectiveness of the thus mixed materials does not lastparticularly long.

From WO 95/20878 a method is known for manufacturing bactericidal orfungicidal plastic bodies. For this a thin layer of silver is firstapplied to a membrane film using thin-film technology. The membrane filmis then broken up. The broken up membrane film is fused on and then putinto the desired shape with conventional techniques.—The method is verytime-consuming and expensive. It requires the manufacturing of a specialintermediate product and its breakup.

From EP 0 190 504 an antimicrobial composition is known which contains 5to 10 weight % of silver. To improve the antimicrobial properties ahydratable or a hydrated oxide is additionally added.

DE 31 10 681 C2 describes a material for bone implants. The material ismade from a polymer to which silver phosphate is added as antimicrobialactive substance.

From WO 81/02667 an antimicrobial surgical implant is known. Metallicsilver is added to the implant as antimicrobial active substance.

WO 82/01990 of this type describes a bone cement based onpolymethylmethacrylat as the main component to which 5 vol. % of asilver salt is added as antimicrobial active substance.

U.S. Pat. No. 5,837,275 discloses an antimicrobial material whichcontains, among others, silver particles with a grain size of less than200 nm. The silver lattice has artificially-created latticeimperfections and flaws to facilitate the release of silver ions.

From WO 84/01721 a material containing silver sulfate or silver acetateis known. Within 24 hours this material releases a concentration of morethan 1 μM of silver ions in a surrounding liquid.

DE 32 288 849 A1 describes a material with a coating of silver.Elementary carbon or titanium is added to the material. The addition isintended to facilitate an increased release of silver ions to thesurroundings.

U.S. Pat. No. 4,849,233 discloses a bone cement to which approximately10 weight % elementary silver is added as well as titanium oxide ortantal oxide. The bone cement is characterized by its high rate ofrelease of silver ions.

The antimicrobial effectiveness of the materials known in accordancewith the state of the art has been proven with the so-called inhibitionzone measurement. The inhibition zone measurement is described, forexample, in Raad I. et al., J. Infec. Dis. 173 (1996). For this thematerial to be tested is placed in a culture medium such as Agar. Due tothe release of antimicrobial acting metallic ions an inhibition zoneforms around the material. The formation and the size of such aninhibition zone has been evaluated in accordance with the state of theart as the indication of the antimicrobial effectiveness of thematerial.

The materials known in accordance with the state of the art have thedisadvantage that they initially release an excessive concentration ofsilver ions. According to more-recent findings, materials which show aninhibition zone are not suitable for use in medical applications. Suchmaterials release silver ions in macroscopic visible amounts to thesurrounding tissue. Such amounts of silver ions are cytotoxic however.To the extent that such materials are approved at all by certifyingauthorities, approval is meanwhile now only given in accordance withpharmaceutical law. Such an approval is extremely expensive andtime-consuming.

Seen as a whole no antimicrobial adhesive and coating material inaccordance with the state of the art is yet known that does not indicatean inhibition zone with the inhibition zone test and is thus notcytotoxic.

Object of the invention is to remove the disadvantages in accordancewith the state of the art. In particular an adhesive and coatingmaterial that can be manufactured as simply and inexpensively aspossible is to be specified which is not cytotoxic and whoseantimicrobial effectiveness lasts as long as possible. As defined in afurther goal of the invention the adhesive and coating material is to bedesigned for as universal use as possible and permit the manufacture ofthin coatings. Furthermore a simple and inexpensive method ofmanufacturing the adhesive and coating material is to be specified.

This object is solved by the features in claims 1, 22 and 23. Usefulembodiments result from the features of claims 2 to 21 and 24 to 35.

According to the invention an antimicrobial adhesive and coatingmaterial is suggested which contains metallic silver particles asantimicrobial component with a content of less than 5 ppm of silver,sodium and potassium ions.—The suggested adhesive and coating materialdemonstrates an antimicrobial effectiveness of particularly longduration. It is not cytotoxic. In other words no inhibition zone can beobserved during the inhibition zone test. This is attributed to thecontinuous low rate of silver ions released by the silver particles anddiffused to the surface of the adhesive and coating material. Accordingto the present state of knowledge, the low rate of release is attributedto the particularly low content of silver, sodium and potassium ionswhich is in total less than 5 ppm. The materials known in accordancewith the state of the art primarily contain silver particles whichinitially release a high rate of silver ions. A high rate of release ofsilver ions is achieved, for example, with a disturbed latticeconstruction of the silver particles or with a high content of ions inthe silver particles. Precisely this is not present in accordance withthe subject of this invention.

The term adhesive and coating material means primarily and generally asynthetically manufactured material with an organic basis. In generalthe material hardens after processing. This can be a paint substance, alacquer, an adhesive, in particular also with a thermoset orthermoplastic basis.

In accordance with a first embodiment the average grain size of theparticles is less than 100 nm, preferably in the range of 5 to 50 nm.Such silver particles are suitable for the manufacture of nano-dispersedantimicrobial adhesive and coating materials.

In accordance with a further embodiment the silver particles are made ofaggregates of primary particles with an average grain size of between 10and 150 nm. Such silver particles are suitable for the manufacture ofso-called nano-porous antimicrobial adhesive and coating materials.

In accordance with an advantageous embodiment the primary particles havean average grain size in the range of 80 to 140 nm. Silver particlescreated from such primary particles demonstrate a particularly goodantimicrobial effectiveness. They are not cytotoxic.

In accordance with an advantageous embodiment the aggregates have anaverage grain size of 1 to 20 μm, preferably 10 to 20 μm. It has shownto be useful that the surface of the aggregates is 3 to 6 m²/g. They canhave a porosity of up to 95%. A porosity of between 70 and 95% has beenshown to be useful. The aforementioned features contribute to a uniformand cytotoxically harmless release of silver ions on the surface of thematerial.

It has been shown to be useful that the antimicrobial adhesive andcoating material is manufactured from at least one liquid organiccomponent. This can be hardened like lacquer or a paint color byevaporating a solvent. However it is also possible to polymerize theorganic component for hardening, for example, via UV light, heat orother physical influences. The antimicrobial adhesive and coatingmaterial can also be manufactured by mixing the organic component withat least one additional liquid organic component. The additional organiccomponent can be, for example, a hardener which causes polymerization.The silver particles can be added immediately to the liquid organiccomponent or also immediately to a liquid precursor product of same.This makes it particularly simple to manufacture a particularlyhomogenous dispersion of silver particles. In particular, it is thus notnecessary to make an intermediate product with a related great expenseand amount of time and then to process this further.

In accordance with a further embodiment 0.01 to 5.0 weight % of silverparticles can be added. Preferably 0.01 to 2.0 weight % are added. Thesilver particles used by the invention have an antimicrobial effect overa long period already in a low concentration without causing a cytotoxiceffect. It has been shown to be useful that the particles are spherical,in particular ball-shaped. This simplifies the mixing of silverparticles into the liquid organic component. A homogenous dispersion canbe made quickly. It is advantageous that the aggregates are completelyinfiltrated with the organic component.

The organic component and/or the additional organic component cancontain an acrylate or a methacrylate as an essential constituent.Furthermore they can contain an epoxide, urethane, silicone orcyanoacrylate as an essential constituent.

In a further embodiment the antimicrobial adhesive and coating materialcontains as further addition cations of at least one of the followingmetals: Au, Pt, Pd, Ir, Sn, Cu, Sb, Zn. The further addition increasesand/or lengthens the period of antimicrobial effectiveness. It has shownto be useful that the cations are bound in ion exchangers, added in theform of a complex or as a salt. The cations can diffuse from theadhesive and coating material to their surface and develop theirantimicrobial effectiveness there. In this connection it has been shownto be useful that the salt of a, preferably polymeric, carboxylic acidis used as the salt.

The adhesive can be a pressure-sensitive adhesive. The organic and/orthe further organic component can contain one or more of the followingconstituents: solvent, filler material, pigment, binding agent,plasticizer, drying accelerator, fungicide. The coating material can bea lacquer, a paint substance or a dispersion which can be hardened.

In further accordance with the invention a use of the adhesive andcoating material provided by the invention is provided for themanufacture and/or coating of wound coverings, bandages, incontinenceproducts, diapers for example, medical devices, packaging materials, forthe coating of walls of buildings, housings and/or components oftechnical devices. For instance the interior walls of the housing ofair-conditioners, the walls of operating rooms, containers for theproduction and storage of perishable foodstuffs, packaging material fordisposable medical devices, disposable medical devices, bandages,medical instruments, etc. can be coated with the material provided bythe invention or made thereof.

In further accordance with the invention a method for the manufacture ofthe adhesive and coating material according to the invention is providedwith the following steps:

-   generation of a silver vapor by sputtering or by vaporization in a    vacuum recipient,-   condensation of the silver vapor so that silver particles are formed    with a content of less than 5 ppm of silver, sodium and potassium    ions,-   mixing of the silver particles with a liquid organic component and-   at least partially hardening of the organic component.

The suggested method is simple and inexpensive to execute.

It can be used to make an antimicrobial adhesive and coating materialwhose antimicrobial effectiveness lasts for a particularly long periodand, at the same time, has no cytotoxic effect on tissue which is incontact with it. The method can be used to make solid adhesive andcoating materials and partially hardened pressure-sensitive adhesives.The method is generally also suitable for the manufacture of plastics,preferably made of at least one liquid component. For example medicaldevices such as catheters and similar can be made from such plastics.

With a first version of the method the silver vapor is condensed duringthe vapor phase so that aggregates are created from primary particleswith an average grain size of 10 to 150 nm which aggregates have anaverage grain size of 1 to 20 μm.

With this version of the method the primary particles are created fromthe vapor phase. The created primary particles have an extremely highsurface energy. When primary particles aggregate to each other thepresent activation energy already causes diffusion processes which causethe formation of sinter necks. Aggregates are formed in which theprimary particles are connected with each other by sinter necks. Highlyporous aggregates can be created in this way.

In accordance with a further version of the method the silver vapor iscondensed on the surface of a liquid so that the silver particles havean average grain size of between 10 and 100 nm. With this version of themethod the formation of agglomerates is prevented by withdrawing fromthe silver particles the activation energy needed to create sinter necksin a condensation process on a liquid surface. Nano-disperse,antimicrobial adhesive and coating materials can be manufactured in thisway.

The liquid can be a precursor product of the organic component or theorganic component. The suggested method is particularly simple toexecute. In a single device a homogenous dispersion of the silverparticles can be made in the organic component or its precursor product.The adhesive and coating material can be further processed by hardeningof the organic component, for example by adding an additional organiccomponent.

For further advantageous embodiments reference is made to the featuresalready described with the antimicrobial adhesive and coating materialwhich features can also be applied appropriately in connection with themethod.

Examples will now be used to describe the invention in more detail basedon the drawings. The figures are listed below:

FIG. 1 Silver particles dispersed in polytetrahydrofuran,

FIG. 2 Silver particles dispersed in diethylhexylphthalat,

FIG. 3 Silver particles dispersed in dimethylsiloxan,

FIG. 4 Documentation of the antimicrobial effect of an epoxy resinadhesive containing silver particles,

FIG. 5A scanning electron microscopic image of a silver aggregate and

FIG. 6 An inhibition zone test of a coating material provided by theinvention.

Manufacturing of the Metallic Silver Particles:

Silver (99.95 silver wire from the Heraeus company) is vaporized bymagnetron sputtering in a vacuum recipient at a temperature of 20° C.and under a pressure of 0.01 to 0.1 mbar in argon atmosphere.Vaporization in the vacuum recipient can also take place thermally, forexample, in a crucible. The silver vapor is then precipitated on thesurface of a liquid or condensed on a cooled surface together with thevaporized liquid. The liquid can be, for example silicon oil,polytetrahydrofuran, diethylhexylphthalat or dimethylsiloxan. The liquidis continuously stirred so that the precipitated or condensed metallicsilver particles are dispersed homogeneously in the liquid. The organiccomponent or a precursor product of the organic component of theadhesive and coating material to be made is preferably used as theliquid.

FIG. 1 shows spherical silver particles dispersed in polytetrahydrofuranin accordance with the aforementioned method.

This is a precursor product of an epoxy resin. It can be seen in FIG. 1that the silver particles have an average grain size of less than 10 nm.

FIG. 2 shows spherical silver particles which have been dispersed indiethylhexylphthalat in accordance with the aforementioned method. Thisis a component for a coating of polyvinyl chloride (PVC). Also herethere is a homogenous dispersion of the silver particles in thecomponent. The silver particles have an average grain size of less than10 nm.

FIG. 3 shows a dispersion of ball-shaped silver particles indimethylsiloxan. This is a component of a silicon adhesive. Again thesilver particles have an average grain size of less than 10 nm here.

The previously described dispersions can then be hardened, for example,by the addition of a further liquid component. They can also be mixedwith functional groups such as acrylate or methacrylate groups, orco-polymerized in case of polytetrahydrofuran for example.

Examples of the manufacturing of antimicrobial adhesive and coatingmaterials are now described.

EXAMPLE 1

Preparation of Bactericidal Silicon Materials:

A component such as a binder of an addition-vulcanizing two-componentsilicon rubber based on polydimethylphenylsiloxan (RTV-S691; Wacker) isdoped with silver particles made via the method described above. Thecomponent is then mixed in the ratio of 9:1 with an additional componentsuch as a hardener. Hardening takes place at T=25° C. The resultingconcentration of silver in the hardened material is 0.01 to 5 weight %,preferably 0.05-1 weight % of silver. The hardenable material can beused immediately as adhesive, lacquer or, after addition of suitablepigments or dyes, also as printer's ink.

EXAMPLE 2

Preparation of Bactericidal Epoxy Resin Adhesives:

A hardener (HV 998, Ciba) of a pasty two-component adhesive with anepoxy resin basis (Araldit AV138M, Ciba) is doped with silvernano-particles using the method described above. The doped hardener ismixed into the epoxy resin and hardened at room temperature. Theconcentration of silver is 0.01 to 5 weight %, preferably 0.1 to 1weight %, of silver in the hardened two-component adhesive. Thehardenable material can be used immediately as adhesive, lacquer or,after addition of suitable pigments or dyes, as printer's ink forexample.

EXAMPLE 3

Preparation of Bactericidal and Bacteriostatic Epoxy Resin Adhesives:

Adhesives are prepared on the basis of cationic hardening cycloaliphaticepoxy resins. The epoxy resin ERL 4221 (Union Carbide) is co-polymerizedwith polytetrahydrofuran (PTHF) with a molecular mass of 1000 (PTHF1000, BASF). PTHF is used for flexibilization or as plasticizer. ThePTHF contains 5 weight % silver incorporated with the method describedabove (designation: PTHF-VERL-Ag). This results in a silver content ofthe samples provided by the invention of 1 weight %. No silver iscontained in comparable examples. The thermal cationic hardening takesplace with the addition of an initiator. For example the iodonium saltRhodorsil 2074 (Rhodia) can be used as initiator withascorbic-acid-6-hexadecant (ASHD) as accelerator or withα,α-dimethyl-benzylpyridinium hexafluoroantimonat (S. Nakano, T. Endo,J. Polym. Sci.: Part A, 34 (1996) 475). Hardening takes place with thefollowing temperature program: 90 min at 80° C., 60 min at 100° C. and60 min at 120° C.

The composition of the individual mixtures in weight % and themicrobiological effect on staphylococcus epidermidis is summarized inthe following table. Microbio- Felxibili- Type of logical Ef- Resinsator Initiator Example fect 79% ERL 20% PTHF 1% α,α-dime- Compari- None4221 thylbenzyl- son pyridinium hexafluoroanti- monat 78% ERL 20% PTHF1% Rhodorsil Compari- None; 4221 2074, 1% ASHD son FIG. 4, sample A 79%ERL 20% PTHF- 1% α,α-Dime- Provided Bacterio- 4221 VERL-Agthylbenzylpyri- by the static; dinium hexa- invention FIG. 4,fluororoantimonat sample B 78% ERL 20% PTHF- 1% Rhosorsil ProvidedBacteri- 4221 VERL-Ag 2074, 1% ASHD by the cidal; FIG. invention 4,sample C

The results shown in FIG. 4 have been determined in accordance with themethod made known from DE 197 51 581 A1. This method is also describedin Bechert, Thorsten et al., Nature Medicine, Vol. 6, No. 8 (09/2000).The disclosed contents of the two aforementioned documents are therebyincluded.

First 8 parallel samples each of the same batch of epoxy resin adhesiveare made. The samples usually have a cylindrical shape. They have alength of approximately 1 cm and a diameter of 2 to 5 mm. Then 200 μl ofthe bacteria-containing solution is filled in each recess of themicro-titer plate. The samples are incubated at 37° C. for one hour. Thesamples are then removed and washed three times with physiologicalbuffers. Then the samples are placed in the recesses of a micro-titerplate which are filled with a minimal medium. Each recess is filled with200 μl of minimal medium. The samples are incubated at 37° C. for 24hours. The samples are then removed and rejected. 50 μl of a full medium(trypcasesoja) are added to each recess of the micro-titer plate. Theclouding or absorption of the solution is then measured at 30-minuteintervals over a period of 48 hours. The solution is held at atemperature of 37° C. The clouding measurement is made with light of awave length of 578 nm via a suitable reading device. Cloudinessindicates that bacteria have been released from the surface of thesample to the environment.

The results shown in FIG. 4 indicate that the bactericidal effect ofadhesives can be controlled by appropriate selection of the initiator.The hardenable material can be used immediately as adhesive, lacquer or,for example, as printer's ink after addition of suitable pigments ordyes.

FIG. 5 shows a scanning electron microscopic image of the silveraggregate provided by the invention. The silver aggregate essentiallyconsists of ball-shaped primary particles with an average grain size ofapproximately 20 nm. The primary particles are connected with each otherprimarily via sinter necks. They form a highly porous framework. Thesilver aggregate shown here has a size of approximately 10 μm. Suchsilver aggregates can also be added to the adhesive and coating materialinstead of the fine silver particles described in the precedingexamples. Comparable results are obtained with this with regard to theantimicrobial effect as well as the inhibition zone test.

FIG. 6 shows an inhibition zone test of an adhesive and coating materialprovided by the invention. This is a polyurethane lacquer to which 0.1weight % silver particles are added. The silver particles areagglomerates such as those shown in FIG. 5. The samples are placed inTSB-Agar as the culture medium to which staphylococcus epidermidis isadded as a test organism. The samples were incubated for 48 hours. AsFIG. 6 illustrates, the samples do not show an inhibition zone. To thisextent they are not viewed as having a cytotoxic effect.

1-35. (canceled)
 36. Antimicrobial adhesive and coating material whichcontains as the antimicrobial component metallic silver particles with acontent of less than 5 ppm of silver, sodium and potassium ions ismanufactured via a method with the following steps: generation of asilver vapor by sputtering or by vaporization in a vacuum recipient,condensation of the silver vapor so that silver particles are formedwith a content of less than 5 ppm of silver, sodium and potassium ionsand mixing of the silver particles with a liquid organic component. 37.Antimicrobial adhesive and coating material as defined in claim 36,wherein, with the method, the organic components are at least partiallyhardened after mixing in silver particles.
 38. Antimicrobial adhesiveand coating material as defined in claim 36, wherein the average grainsize of the particles is smaller than 100 nm, preferably in the range of5 to 50 nm.
 39. Antimicrobial adhesive and coating material as definedin claim 36, wherein the silver particles are formed of aggregates ofprimary particles with an average grain size of between 10 and 150 nm.40. Antimicrobial adhesive and coating material as defined in claim 39,wherein the primary particles have an average grain size in the range of80 to 140 nm.
 41. Antimicrobial adhesive and coating material as definedin claim 39, wherein the aggregates have an average grain size of 1 to20 μm, preferably 10 to 20 μm.
 42. Antimicrobial adhesive and coatingmaterial as defined in claim 39, wherein the aggregates have a porosityof up to 95%.
 43. Antimicrobial adhesive and coating material as definedin claim 39, wherein the aggregates have a surface area of 3 to 6 m² pergram.
 44. Antimicrobial adhesive and coating material as defined inclaim 36, wherein the silver has an essentially undisturbed latticestructure.
 45. Antimicrobial adhesive and coating material as defined inclaim 36, wherein it is made of at least one liquid organic component.46. Antimicrobial adhesive and coating material as defined in claim 36,wherein it is made by mixing the organic component with at least oneadditional organic component.
 47. Antimicrobial adhesive and coatingmaterial as defined in claim 36, wherein the silver particles are mixedimmediately with the liquid organic components or immediately with aliquid precursor product of same.
 48. Antimicrobial adhesive and coatingmaterial as defined in claim 36, wherein 0.01 to 5.0 weight % of silverparticles are mixed in.
 49. Antimicrobial adhesive and coating materialas defined in claim 36, wherein the aggregates are completelyinfiltrated with the organic component.
 50. Antimicrobial adhesive andcoating material as defined in claim 36, wherein the organic componentand/or the additional organic component is essentially composed of anacrylate or methacrylate.
 51. Antimicrobial adhesive and coatingmaterial as defined in claim 36, wherein the organic component and/orthe additional organic component is essentially composed of an epoxide,urethane, silicone or cyanoacrylate.
 52. Antimicrobial adhesive andcoating material as defined in claim 36, wherein as a furtherconstituent cations of at least one of the following metals arecontained: Au, Pt, Pd, Ir, Sn, Cu, Sb, Zn.
 53. Antimicrobial adhesiveand coating material as defined in claim 36, wherein the cations arebound in ion exchangers and added in the form of a complex or as salt.54. Antimicrobial adhesive and coating material as defined in claim 36,wherein the salt is a salt of a, preferably polymeric, carboxylic acid.55. Antimicrobial adhesive and coating material as defined in claim 36,wherein the adhesive and coating material is an adhesive, in particulara pressure-sensitive adhesive.
 56. Antimicrobial adhesive and coatingmaterial as defined in claim 36, wherein the organic and/or theadditional organic component contains one or more of the followingconstituents: solvent, filler material, pigment, binding agent,plasticizer, drying accelerator, fungicide.
 57. Antimicrobial adhesiveand coating material as defined in claim 36, wherein the adhesive andcoating material is a lacquer, a paint substance or a dispersion whichcan be hardened.
 58. Use of the antimicrobial adhesive and coatingmaterial as defined in claim 36 for the manufacture and/or coating ofwound coverings, bandages, incontinence products, medical devices,packaging materials, for the coating of walls of buildings, housingsand/or components of technical devices.
 59. Method for the manufactureof an antimicrobial adhesive and coating material as defined in claim36, with the following steps: generation of a silver vapor by sputteringor by vaporization in a vacuum recipient, condensation of the silvervapor so that silver particles are formed with a content of less than 5ppm of silver, sodium and potassium ions and mixing of the silverparticles with a liquid organic component.
 60. Method as defined inclaim 59, wherein the organic component is at least partially hardenedafter the mixing in of silver particles.
 61. Method as defined in claim59, wherein the silver vapor is condensed during the vapor phase so thataggregates are created from primary particles with an average grain sizeof 10 to 150 nm which aggregates have an average grain size of 1 to 20μm.
 62. Method as defined in claim 59, wherein the silver vapor iscondensed on the surface of a liquid so that the silver particles havean average grain size of between 10 and 100 nm.
 63. Method as defined inclaim 59, wherein the organic component or a precursor product of sameis used as liquid.
 64. Method as defined in claim 59, wherein the silverparticles are added to a precursor product instead of the organiccomponent and then the organic component is made.
 65. Method as definedin claim 59, wherein 0.01 to 5.0 weight % of silver particles are addedto the organic component.
 66. Method as defined in claim 59, wherein theorganic component is mixed with at least one further liquid organiccomponent.
 67. Method as defined in claim 59, wherein the organiccomponent and/or the additional organic component are/is essentiallycomposed of an acrylate or a methacrylate.
 68. Method as defined inclaim 59, wherein the organic component and/or the additional organiccomponent are/is essentially composed of an epoxide, urethane, siliconeor cyanoacrylate.
 69. Method as defined in claim 59, wherein cations ofat least one of the following metals are added to the organic componentand/or the additional organic component: Au, Pt, Pd, Ir, Sn, Cu, Sb, Zn.70. Method as defined in claim 59, wherein the cations are bound in ionexchangers and are added at least to the first organic component in theform of a complex or as salt.
 71. Method as defined in claim 59, whereinthe salt is a salt of a, preferably polymeric, carboxylic acid. 72.Method as defined in claim 59, wherein one or more of the followingconstituent is/are added to the organic component and/or the additionalorganic component: solvent, filler material, pigment, binding agent,plasticizer, drying accelerator, fungicide.